As a member of grouper family

Epinephelus coioides

is one of the most commonly cagecultured species in southern areas of China. Although groupers production are becoming more popular in worldwide markets

the aquaculture industry of this specie is still poorly developed when compared to other marine fish species aquacultured such as stripped bass

cobia

gilthead seabream. Despite of other factors affecting the expansion of cultured area for groupers

the price and steady provision of larvae are important determinants

which depend on effectiveness of the larval culture. Nowadays

grouper larvae for aquaculture in China are mostly from Hainan province due to its favorable conditions for larval culture such as good water quality

suitable temperature. However

mass production of grouper larvae is still encountering many difficulties

and high mortalities were often reported in grouper larvae culture

which affects its industry development. The low survival rate of grouper larvae cultured is due to the poor firstfeeding conditions such as live prey deprivation or environmental stress. The aim of this paper is to compare and discuss effects of various water cultivation regimes on plankton community in grouper

Epinephelus coioides

larviculture ponds (2.5 m × 4.0 m ×1.1 m，W×L×H). Four cultivation regimes were designed. In group 1 (G1) and group 2 (G2)

two different levels of prepared effective microorganisms solution (EMS) (40 mL·m

-3

for G1 and 80 mL·m

-3

 for G2

respectively) and two different levels of shrimp chip (SC) (4 g·m

-3

 for G1 and 8 g·m

-3

 for G2

respectively) were daily added one week prior to hatching. Effective Microorganisms comprised of

Clostridiums

Photosynthetic bacterium

Lactobacillus

Saccharomyces

and

Nitrobacteria

species. In group 3 (G3) and group 4 (G4)

only prepared

Platymonus

spp. solution (PS) was daily added one day prior to hatching at a level of 2.5 L·m

-3

 for G3 and a level of 5 L·m

-3

 for G4

respectively. Each group contained three replicates. Results showed that G1 and G2 had more species of phytoplankton and zooplankton than G3 and G4 did. Both phytoplankton and zooplankton populations density could be significantly improved by EMS and SC additions. G2 had a high density of zooplankton populations (1.3 × 10.5 ~2.1 × 10.5 ind·L

-1

) during the larval culture period. Zooplankton populations density in G1 and G2 were significantly higher than noted in G3 and G4 during the larval culture period (P≤0.05). In the present studies

high density of zooplankton populations observed in G2 indicates that effective microorganisms do have a positive role in improving zooplankton biomass of grouper experiment ponds. Additionally

a brown water environment came into being in ponds which been added shrimp chip and brown sugar. This may play a role in alleviating possible external stress to grouper larvae. Overall

abundant zooplankton biomass as live prey for grouper larvae growth would be constantly attained by additions of EMS and together with SC.